2. The point of the PLC is to avoid tying identity to keys, specifically for the point that if you lose your keys, you lose your identity. In reality, no body wants that as part of the system

3. The soup means you need to index everything. There is no Bluesky server to send things to, only your PDS. Your DID is how I know what PDS to talk to to get your records

We can have both a directory and use content addressable storage and give people the option of using their own keypairs. They are not mutually exclusive. Bluesky chooses to have a central directory and index.